A document scanner moves a document from an input tray, through a transport path and creates an image of the document as it moves past a stationary imaging capture device such as a charge coupled device (CCD) or CIS. Sensors in the transport are used to make sure the document enters the transport correctly. Depending on the type of document or document characteristics, the operator must select functions and features to optimize the scanner to accommodate the specific requirements for a particular document.
A document scanner includes an input tray for holding documents. A transport system picks the top-most document from the input tray and moves it past one or more document detection sensors as well as an image capture device which acquires an image of the document being scanned on its way to the output tray. The image captured is stored in a buffer memory which is analyzed by an image processor.
The image processor determines characteristics of documents being scanned, and the documents are processed based on the characteristics. The document characteristic may include the document length, width, position, color, type, or condition of the document. Document detection sensors such as ultrasonic sensors can be used to detect multiple documents fed into the transport at the same time. By combining the ultrasonic data with the characteristics obtained from the document's image data, an accurate correlation can be made to determine which zone or zones should be used or ignored and which ultrasonic sensor data should be excluded or included during further processing of at least one location within the document based on at least one characteristic.
In a document scanner, the documents to be scanned may vary by size, weight, color content, physical condition, or other characteristics, which may require different scanner features to be enabled or operator actions to be employed for the most optimal and efficient mode of operation. Since the scanner is not typically programmed with specific requirements on a document-by-document basis, the user may default the scanner to a less efficient set of settings that will process all documents within a batch. Alternately, the operator may manually sort the documents based on common document characteristics. Documents could be sorted based on document characteristics, such as length, width, weight, color, physical condition, or document type.
Prior art, such as commonly-assigned U.S. patent application Ser. No. 13/272,616, accomplishes this by adding an external image device to the input tray. This method adds additional cost and complexity by adding additional circuitry to support the external camera. In addition since the document is imaged before it enters the transport, any document skew, shifting or slippage due to the feed roller introduces error that is difficult to correct for after the document has move into the transport. Additionally, mischaracterization of the top-most document's length and size due to the inability to disassociate this document from others in the stack can lead to subsequent document classification scanning errors.
Knowledge of these many different document characteristics can enable the proper selection of scanner features to improve the efficiency of the scanning process or enable other features which may provide specific applications required by a particular type, style, or size of document. There is a need, therefore, for detection of document characteristics to optimize the operation of the scanner.